Polyaniline–single walled carbon nanotube composite – a photocatalyst to degrade rose bengal and methyl orange dyes under visible-light illumination

Abstract

The polyaniline/single walled carbon nanotube (PANI–SWCNT) composites were prepared by the polymerization of an aniline monomer in the presence of sulfosalicylic acid with SWCNT under in situ conditions. PANI and PANI–SWCNT composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultra violet-visible spectroscopy (UV-Vis), Fourier transform infra-red spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and Brunauer–Emmett–Teller (BET) analysis. The application of the composites as a recyclable photocatalysts with visible-light-driven photocatalytic activity and photostability for the degradation of organic dyes – Rose Bengal (RB) and Methyl Orange (MO) – is demonstrated. PANI–SWCNT composite, with 2 weight% SWCNT content, has emerged as the best with degradation efficiencies of 95.91% and 90.34% against the performance of PANI with degradation efficiencies of 85.2% and 75.9% for RB and MO within 10 and 30 minutes, respectively. The synergistic effect between PANI and SWCNT is found to impart improved photogenerated carrier separation in the composite. A possible photocatalytic mechanism on the enhancement of the visible light performance of the composite over pure PANI is discussed based on the results of an active species trapping experiment.